iTunes/iTouch help

Hi guys,

hope you can help me here, ive had an ipod Touch since its been out.
but have never tried to put a movies on it untill today.

I have hit a problem when its in itunes it will convert
it sync's it to my ipod no problem but
wheni try and play all i get is a white screen/no sound
but the time still goes up.

Any help will be sound.